THE POTATO 525 



cooked potatoes and represents the average of 

 many American analyses. For comparison the 

 composition of white bread is also given. 



"The corky skin of the potato makes up about 

 2.5 per cent of the whole, and the cortical layer 

 8.5 per cent., leaving 89 per cent, for the medul- 

 lary areas. Theoretically, the skin is the only 

 refuse or inedible material in the potato, but in 

 practice a considerable part of the cortical layer is 

 usually removed with it. 



"The edible portion of the potato i. e., the 

 tuber without the corky skin holds on an average 

 about 78 per cent, water, and so only about 20 

 per cent of the whole tuber has a direct food value. 



"The illustration shows very plainly that the 

 bulk of the potato tuber is water. The stage of 

 growth and other conditions affect the proportion 

 present, young tubers being more juicy or watery 

 than those which are fully developed. 



"The carbohydrates are by far the most abun- 

 dant of the nutrients. Of the 18.4 per cent, less 

 than 0.5 per cent, is made up of cellulose, yet one 



